INVESTMENTS:

Cash, cash equivalents and short-term investments:

The short-term investments are classified as available-for-sale securities. The cash, cash equivalents and short-term investments at March 31, 2017 and December 31, 2016 were as follows:



	March 31, 2017
	Amortized Cost			Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	54,259		$	—	$	—		$	54,259
Money market funds	4,098			—		—			4,098
Certificates of deposit	79,147			—		—			79,147
U.S. Government and agency securities	44,741			1		(106		)	44,636
Commercial paper	30,318			7		(9		)	30,316
Corporate bonds	89,131			51		(100		)	89,082
Municipal bonds	8,642			1		(8		)	8,635
Foreign government bonds	15,021			5		(9		)	15,017
Total	325,357			65		(232		)	325,190
Less amounts classified as cash and cash equivalents	(58,357		)	—		—			(58,357		)
Short-term investments	$	267,000		$	65	$	(232	)	$	266,833



	December 31, 2016
	Amortized Cost			Unrealized Gains		Unrealized Losses			Estimated Fair Value
	(in thousands)
Cash	$	54,947		$	—	$	—		$	54,947
Money market funds	1,833			—		—			1,833
Certificates of deposit	78,643			—		—			78,643
U.S. Government and agency securities	56,431			2		(86		)	56,347
Commercial paper	29,486			—		(3		)	29,483
Corporate bonds	94,292			37		(167		)	94,162
Municipal bonds	7,718			—		(12		)	7,706
Foreign government bonds	5,327			—		(7		)	5,320
Total	328,677			39		(275		)	328,441
Less amounts classified as cash and cash equivalents	(56,780		)	—		—			(56,780		)
Short-term investments	$	271,897		$	39	$	(275	)	$	271,661

Interest income and gains (losses) on short-term investments, net were $0.9 million and $(0.1) million for the three months ended March 31, 2017 and 2016, respectively. At March 31, 2017, gross unrealized losses on investments that were in a gross unrealized loss position for greater than 12 months were immaterial. These investments were not deemed to be other-than-temporarily impaired and the gross unrealized losses were recorded in other comprehensive income (loss) ("OCI").

The contractual maturities of short-term investments at March 31, 2017 and December 31, 2016 were as follows:



	March 31, 2017				December 31, 2016
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
	(in thousands)
Due in less than one year	$	155,609	$	155,499	$	157,270	$	157,163
Due in one to three years	111,391		111,334		114,627		114,498
	$	267,000	$	266,833	$	271,897	$	271,661

Equity investments in privately-held companies:

As of March 31, 2017 and December 31, 2016, the Company held a total of $19.7 million and $12.7 million, respectively, in equity investments in privately-held companies.